We plan to investigate the effects of naturally occurring catechol amines on the retinal circulation using the fluorescein densitometry technique for estimation of relative retinal blood flow. Adrenalin, nor-adrenalin and dopamine will be administered in physiologic and pharmacologic dose levels and evaluated both in terms of systemis and local response. Some of these assays will be repeated after treatment of the retinal vessels to alter the blood brain barrier. To our knowledge no such studies have as yet been done on the eye. BIBLIOGRAPHIC REFERENCE: Horiuchi, T., Gass, J.D.M., and David, N.J.: Arteriovenous malformation in the retina of a monkey. Am. J. Ophthal., 82: 896-904, 1976.